High pressure press



Jan. 4, 1966 D. H. NEWHALL 3,227,068

HIGH PRESSURE PRESS Filed Sept. 10, 1963 FIGI ,M

FIG. 2

ATTORNEY United States Patent C) 3,227,068 HIGH PRESSURE PRESS Donald H. Newhall, Walpole, Mass, assignor to Harwood Engineering Company Walpole, Mass, a corporation of Massachusetts Filed Sept. 10, 1963, Ser. No. 307,960 7 Claims. (Cl. 100--93) as a function of pressure, temperature, and, if so desired,

at varying shear rates.

More specifically it is an object of the invention to provide an anvil comprising an anvil member and a massive supporting piece therefor constructed and assembled in a novel manner to provide an anvil assembly of great strength and durability and in which the force exerted thereby is concentrated in a relatively small anvil tip suitable for the unobstructed placement of auxiliary heating and other elements adjacent to the point of engagement of the anvils with a specimen.

In accordance with the invention an improved anvil is provided for use in a high pressure press in which there is provided an anvil contact member of generally rounded shape of a very hard material which is driven into and embedded in a supporting piece to a point slightly beyond the section of greatest diameter of said anvil contact member, said supporting piece being of a less hard, substantially more ductile and elastic material than said anvil contact member, so that the material of which the supporting piece is made is plastically deformed to accommodate the anvil contact member. The anvil contact member, so embedded in a closely adhering socket in the supporting piece produced by the press-fitting operation, produces a highly eflicient anvil in which the anvil contact member is at all times strengthened by the radially directed supporting pressures exerted over the whole hemispherical interface between the anvil contact member and the socket.

A feature of the invention consists in the particular construction of the anvil contact member which is generally round in shape being symmetrically formed with respect to its thrust axis in the press, having the outer apex slabbed off to form a flat specimen engaging surface and having portions of the under sides thereof slabbed off to form flats which adhere to correspondingly formed portions of the supporting socket to secure the anvil contact member rigidly in position.

It is a further object of the invention to provide a pair of opposed anvils for use in a high pressure press capable of exerting very great pressures of which the individual anvil contact members are so constructed and supported as to project a substantial distance above their supporting pieces providing a free space of substantial depth in a vertical direction about said projecting anvil contact members, said free space being Well adapted for the location therein of an electrical induction heating coil and adjacent shielding devices for applying heat to the specimen without at the same time causing undue heating and consequent injury to the adjacent anvil members.

The several features of the invention together with the advantages to be obtained thereby will be readily understood by one skilled in the art from the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a somewhat fragmentary detail view in eleice vation of an opposed anvil press, the parts being shown in section; and

FIG. 2 is a detail sectional view in elevation illustrating a modified form of anvil contact member press fitted into a metallic supporting piece.

The high pressure press which forms the subject matter of the invention comprises generally a. pair of opposed anvils 10 and 12 consisting of massive supporting pieces 14 and 16 which provide support respectively for generally rounded anvil contact members 18 and 20 having opposed flat specimen engaging surfaces 22 and 24. Inasmuch as the opposed anvils referred to are identical in construction, only the lower of the two anvils comprising the anvil contact member 18 and supporting piece 14 will be hereinafter more fully described. 7

The anvil contact member 18 is generally round in shape, having a continuously curved surface which is symmetrical about the thrust axis, a slabbed off top portion providing the fiat specimen engaging surface 22, and slabbed off under portions providing the flats 26, 27 and 28 above referred to. The anvil contact member is made of a very hard material which may be, for example, hard steel, glass, sapphire, a metal carbide such as tungsten carbide or other similarly hard material of great strength. The anvil contact member in the preferred embodiment shown takes the form of a sphere. It will be understood, however, that other solids of revolution may be employed which are symmetrical about the thrust axis of the press including ellipsoidal and similar rounded. shapes. While in the preferred embodiment of the invention shown flat holding surfaces are employed, it will be understood that a similar effect may be produced by any suitable alteration from the arcuate contour of the curved surface of the anvil contact member.

The support piece 14 in which the anvil support member 18 is embedded and supported may be composed of any suitable material as, for example, a hard steel having suitable qualities of hardness, ductility under extreme pressure and a substantial degree of elasticity. In order that the anvil may be assembled in accordance with the method herein disclosed, it is essential that the supporting piece 14 be substantially less hard and more ductile than the anvil contact member 18.

As shown in the drawing the round anvil contact member 18 is embedded in the socket formed in the surface of the supporting piece 14 to a depth of slightly more than half so that a section of the anvil contact member 18 of maximum diameter in a horizontal plane is slightly submerged below the surface of the support piece. With the construction above described, the support piece 14 provides a maximum of support for the anvil contact member 18 by virtue of the very large supporting pressure which is exerted over the entire interface between the hemispherical socket and the lower embedded portion of the anvil contact member. Further, the elastic recovery of the displaced material comprising the socket formed by the press fitting operation locks and holds the anvil member 18 in said socket. The flats 26, 27 and 28 are tightly fitted to correspondingly formed surface areas of the socket.

In acordance with the invention the anvil contact member 18 is press-fitted into the supporting piece 14 to a depth which causes a transverse section of the anvil contact member 13 of maximum diameter to be submerged below the lip of the socket by a small amount. The highly compressed edge of the socket formed in the metallic supporting piece will now undergo some elastic reformation as the pressure tends to be withdrawn causing constriction of the edge to effectively lock the anvil member 18 into position in the block.

In the embodiment shown the supporting piece member 14 is preferably formed of a hard steel having a degree of hardness in the order of 30 to 40 on the Rockwell C scale, and the anvil member is preferably formed of tungsten carbide having a hardness of roughly 80 to 95 on the Rockwell C scale. It will be understood that materials other than steel may be employed having similar properties of strength, ductility under extreme pressure, and a degree of elasticity sufficient to cause the aperture lip formed by the press fitting operation to engage and hold the anvil member in its press-fit position. The anvil contact member 18 may be composed of other materials having suitable hardness and strength characteristics as for example, hardened steel, glass, or sapphire. It is essential that the anvil member 18 be made of a material harder and less ductile than the supporting piece 14, to permit the press fitting of the spherically shaped anvil member 18 into the supporting piece 14 in acordance with applicants method, to a depth slightly beyond the greatest diameter of the ball in order that the elastic covering of the aperture is effective to lock the anvil element into the supporting block 14.

The rounded shape of the anvil member 18, and the press-fitted engagement of the anvil member 18 with the anvil supporting piece 14 causes the extreme pressure concentrated on the relatively small specimen engaging flat 22 to be spread out with a reasonable degree of uniformity over the substantially larger hemispherical area of contact of the anvil member with the supporting piece 14.

The arrangement is such that a force of maximum intensity applied over a large area to the relatively softer more ductile anvil supporting piece 14 may be successfully concentrated into the anvil member 18 and is thereafter still further concentrated on the much smaller specimen supporting area 22 minimizing the risk of breaking or crushing the anvil.

A feature of applicants improved construction consists in the generally rounded shape of the anvil member flatttened only to provide a substantial specimen supporting surface and to prevent turning of the anvil in its socket. This shape is of substantial value to assist in the press fitting operation in which stresses sufficient to cause flow of the metal comprising the anvil supporting piece are set up in all directions tending to compress and to further harden and strengthen the areas of the supporting piece adjacent to the socket thus formed.

Applicant has found that a rounded generally spheroidal contour of the anvil member provides the greatest degree of strength in the anvil structure while permitting the surface of the anvil to be projected upwardly a maximum distance from the surface of the supporting piece 14. It will be understood that some deviation may be permitted from a true spherical shape within the limits of the invention. The shape of the anvil member may be defined as a surface of revolution about a vertical axis, which is curved also inwardly from each side of an intermediate maximum circumference in a horizontal plane to form a spherical, ellipsoidal or similar rounded shape.

The opposed anvils above described are particularly well adapted for use in combination with an electrical induction heating unit which in the embodiment shown comprises a closed loop 30 disposed in a horizontal plane which passes through a specimen mounted between the opposed anvils. The loop 30 surrounds the specimen and is of sufficient diameter to permit the placing of flat ring-shaped electrical shielding elements 32 and 34 above and below the coil 30 so that the apertures therein are engaged against the adjacent rounded surfaces of the respective anvil members 18 and 2th.

During the operation of the press a high frequency current is passed through the coil 36? setting up a high requency magnetic field which is employed to heat the specimen.

The shielding elements 32, 3d confine the magnetic field within a flat space which is sufficiently narrow to .avoid any substantial heating of the adjacent anvil members by the magnetic fiux generated.

FIG. 2 illustrates a modified form of the invention in which an anvil contact member 40 ellipsoidal in shape is pressfitted into a massive metallic supporting piece 42 having a top surface substantially larger in area than that occupied by the anvil contact member 40 embedded therein. The anvil contact member 40 is a solid of revolution symmetrically formed about a vertical thrust axis but wider than it is high. The ellipsoidal shape illustrated has the advantage that the angle of departure between the fiat specimen receiving face 44 and the adjacent curved surface of the anvil contact member 40 can be made smaller than the corresponding angle formed between the surface 22 and adjacent rounded surface of the anvil contact member 18. The additional lateral spread of the member 46 to the point at which it is engaged with the surface of the supporting piece 42 provides additional support for the anvil member, both internally and externally with relation to the supporting piece 42. The rounded relatively shallow socket formed by engagement with the press fitted anvil contact member 40 also provides a somewhat increased area of support for the anvil contact member about the interface between the anvil contact member and socket. The construction shown in FIG. 2 may therefore be regarded as slightly stronger than the structure of FIG. 1. The greater strength referred to is obtained without sacrificing to any degree the advantages obtained by the spherical shape of the anvil contact member 18 of FIG. 1. The invention having been described what is claimed 1. For use in a high pressure press, having opposed anvils operable along a thrust axis, a said anvil which comprises a generally round anvil contact member formed of a very hard material to withstand extreme pressures without deformation or crushing of said member, and having a continuously curved surface symmetrical about said thrust axis and a cross section of maximum diameter intermediate the upper and lower extremities of said anvil contact member, said anvil contact member having the upper extremity thereof formed with a fiat specimen engaging surface of substantially less area than said cross section of maximum diameter and with adjacent rounded surfaces sloping downwardly at a small angle of departure from said flat surface, and having the lower rounded portion thereof formed with holding surfaces formed as alterations from the normal curvature of said lower curved surface, and a supporting base having an anvil contact member supporting surface area large as compared with said cross section of maximum diameter, said base being formed of a metallic material having a substantially lowerdegree of hardness than said anvil contact member, ductility under extreme pressure, and a substantial degree of elasticity, said anvil contact member being press fitted into said base to a depth byeond said maximum diameter of said anvil contact member thereby forming a holding socket for said anvil contact member of which the displaced metal at the interface between said socket and anvil contact member including the lip portion thereof are elastically engaged with said anvil contact member both above and below said transverse plane of maximum diameter to provide a locking engagement therebetween, said displaced metal conforming to said holding surfaces to resist rotational displacement of said anvil contact member under pressure.

2. An anvil for use in a high pressure press having opposed anvils along a thrust axis according to claim 1 of which the anvil contact member is formed of a material having a hardness of to on the Rockwell C scale, and the metallic supporting piece is formed of a metal having a degree of hardness in the order of 30 to 40 on the Rockwell C scale.

3. In a high pressure press according to claim 1, the

combination of two identical opposed anvils operable along a thrust axis, each said anvil having the specimen contact surface thereof raised substantially above the surface of the support piece, and an induction heating unit comprising a closed electrical heating loop disposed in a transverse plane passing between said specimen engaging surface, and circular shielding elements.

4. An anvil for use in a high pressure press having opposed anvils along a thrust axis according to claim 1 in which any said holding surface is a flat surface.

5. An anvil for use in a high pressure press having opposed anvils along a thrust axis according to claim 1 in which the anvil contact member is spherical in shape.

6. An anvil for use in a high pressure press having opposed anvils along a thrust axis according to claim 1 in which said anvil contact member is ellipsoidal in vertical profile providing a maximum cross sectional diameter intermediate the upper and lower extremities of said anvil contact member which is somewhat greater than the diameter of said anvil contact member taken along the thrust axis.

7. For use in a high pressure press, having opposed anvils operable along a thrust axis, a said anvil which comprises a generally round anvil contact member formed of a very hard material to withstand extreme pressures without deformation or crushing of said member, and having a continuously curved surface symmetrical about said thrust axis and ellipsoidal in vertical section, providing a maximum cross section intermediate the upper and lower extremities of said anvil contact member having a diameter somewhat greater than the diameter of said anvil contact member taken along the thrust axis, said anvil contact member having the upper extremity thereof formed with a flat specimen engaging surface of substantially less area than said cross section of maximum diameter, and with adjacent rounded surfaces sloping downwardly at a small angle of departure from said fiat surface, and a supporting base having an anvil contact member supporting surface area large as compared with said cross section of maximum diameter, said base being formed of a metallic material having a substantially lower degree of hardness than said anvil contact member, ductility under extreme pressure, and a substantial degree of elasticity, said anvil contact member being press fitted into said base to a depth beyond said maximum cross sectional diameter of said anvil contact member thereby forming a holding socket for said anvil contact member of which the displaced metal at the interface between said socket and anvil contact member including the lip portion thereof are elastically engaged with said anvil contact member both above and below said transverse plane of maximum diameter to provide a locking engagement therebetween, and of which the displaced metal at said interface with the ellipsoidally curved lower rounded portion of said anvil contact member provides a holding surface shaped to prevent rotational displacement of said anvil contact member about a transverse axis under pressure directed in the direction of said thrust axis.

References Cited by the Examiner UNITED STATES PATENTS 1,798,738 3/1931 Hoern. 2,506,765 5/1950 Bach 29525 X 2,622,271 12/1952 Gent et al. 181 2,622,272 12/1952 Haring et al. 181 X 3,096,544 7/1963 Lundblad 1816.5 3,100,436 8/1963 McNeill et al. -93

WALTER A. SCHEEL, Primary Examiner.

LOUIS O. MAASSEL, Examiner. 

1. FOR USE IN A HIGH PRESSURE PRESS, HAVING OPPOSED ANVILS OPERABLE ALONG A THRUST AXIS, A SAID ANVIL WHICH COMPRISES A GENERALLY ROUND ANVIL CONTACT MEMBER FORMED OF A VERY HARD MATERIAL TO WITHSTAND EXTREME PRESSURES WITHOUT DEFORMATION OR CRUSHING OF SAID MEMBER, AND HAVING A CONTINUOUSLY CURVED SURFACE SYMMETRICAL ABOUT SAID THRUST AXIS AND A CROSS SECTION OF MAXIMUM DIAMETER INTERMEDIATE THE UPPER AND LOWER EXTREMITIES OF SAID ANVIL CONTACT MEMBER, SAID ANVIL CONTACT MEMBER HAVING THE UPPER EXTREMITY THEREOF FORMED WITH A FLAT SPECIMEN ENGAGING SURFACE OF SUBSTANTIALLY LESS AREA THAN SAID CROSS SECTION OF MAXIMUM DIAMETER AND WITH ADJACENT ROUNDED SURFACES SLOPING DOWNWARDLY AT A SMALL ANGLE OF DEPARTURE FROM SAID FLAT SURFACE, AND HAVING THE LOWER ROUNDED PORTION THEREOF FORMED WITH HOLDING SURFACES FORMED AS ALTERATIONS FROM THE NORMAL CURVATURE OF SAID LOWER CURVED SURFACE, AND A SUPPORTING BASE HAVING AN ANVIL CONTACT MEMBER SUPPORTING SURFACE AREA LARGE AS COMPARED WITH SAID CROSS SECTION OF MAXIMUM DIAMETER, SAID BASE BEING FORMED OF A METALLIC MATERIAL HAVING A SUBSTANTIALLY LOWERDEGREE OF HARDNESS THAN SAID ANVIL CONTACT MEMBER, DUCTILITY UNDER EXTREME PRESSURE, AND A SUBSTANTIAL DEGREE OF ELASTICITY, SAID ANVIL CONTACT MEMBER BEING PRESS FITTED INTO SAID BASE TO A DEPTH BEYOND SAID MAXIMUM DIAMETER OF SAID ANVIL CONTACT MEMBER THEREBY FORMING A HOLDING SOCKET FOR SAID ANVIL CONTACT MEMBER OF WHICH THE DISPLACED METAL AT THE INTERFACE BETWEEN SAID SOCKET AND ANVIL CONTACT MEMBER INCLUDING THE LIP PORTION THEREOF ARE ELASTICALLY ENGAGED WITH SAID ANVIL CONTACT MEMBER BOTH ABOVE AND BELOW SAID TRANSVERSE PLANE OF MAXIMUM DIAMETER TO PROVIDE A LOCKING ENGAGEMENT THEREBETWEEN, SAID DISPLACED METAL CONFORMING TO SAID HOLDING SURFACES TO RESIST ROTATIONAL DISPLACEMENT OF SAID ANVIL CONTACT MEMBER UNDER PRESSURE. 